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Man Z, Zhang J, Liu J, Liu L, Yang J, Cao Z. Process-Based Modeling of Phenology and Radial Growth in Pinus tabuliformis in Response to Climate Factors over a Cold and Semi-Arid Region. PLANTS (BASEL, SWITZERLAND) 2024; 13:980. [PMID: 38611511 PMCID: PMC11013837 DOI: 10.3390/plants13070980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 03/18/2024] [Accepted: 03/28/2024] [Indexed: 04/14/2024]
Abstract
(1) Background: Climate change significantly impacts the phenology and dynamics of radial tree growth in alpine dryland forests. However, there remains a scarcity of reliable information on the physiological processes of tree growth and cambial phenology in response to long-term climate change in cold and semi-arid regions. (2) Methods: We employed the process-based Vaganov-Shashkin (VS) model to simulate the phenology and growth patterns of Chinese pine (Pinus tabuliformis) in the eastern Qilian Mountains, northeastern Tibetan Plateau. The model was informed by observed temperature and precipitation data to elucidate the relationships between climate factors and tree growth. (3) Results: The simulated tree-ring index closely aligned with the observed tree-ring chronology, validating the VS model's effectiveness in capturing the climatic influences on radial growth and cambial phenology of P. tabuliformis. The model outputs revealed that the average growing season spanned from mid-April to mid-October and experienced an extension post-1978 due to ongoing warming trends. However, it is important to note that an increase in the duration of the growing season did not necessarily result in a higher level of radial growth. (4) Conclusions: While the duration of the growing season was primarily determined by temperature, the growth rate was predominantly influenced by water conditions during the growing season, making it the most significant factor contributing to ring formation. Our study provides valuable insights into the potential mechanisms underlying tree growth responses to climate change in cold and semi-arid regions.
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Affiliation(s)
- Zihong Man
- Gansu Liancheng Forest Ecosystem Field Observation and Research Station, Lanzhou University, Lanzhou 730333, China
- Liancheng National Nature Reserve in Gansu, Lanzhou 730300, China
| | - Junzhou Zhang
- Gansu Liancheng Forest Ecosystem Field Observation and Research Station, Lanzhou University, Lanzhou 730333, China
- Key Laboratory of Western China’s Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
| | - Junjun Liu
- Gansu Liancheng Forest Ecosystem Field Observation and Research Station, Lanzhou University, Lanzhou 730333, China
- Key Laboratory of Western China’s Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
| | - Li Liu
- Gansu Liancheng Forest Ecosystem Field Observation and Research Station, Lanzhou University, Lanzhou 730333, China
- Key Laboratory of Western China’s Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jiqin Yang
- Gansu Liancheng Forest Ecosystem Field Observation and Research Station, Lanzhou University, Lanzhou 730333, China
- Liancheng National Nature Reserve in Gansu, Lanzhou 730300, China
- Key Laboratory of Western China’s Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
| | - Zongying Cao
- Gansu Liancheng Forest Ecosystem Field Observation and Research Station, Lanzhou University, Lanzhou 730333, China
- Key Laboratory of Western China’s Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
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Zhang X, Tong C, Fang D, Mei T, Li Y. Different hydraulic and photosynthetic responses to summer drought between newly sprouted and established Moso bamboo culms. FRONTIERS IN PLANT SCIENCE 2023; 14:1252862. [PMID: 37900750 PMCID: PMC10602750 DOI: 10.3389/fpls.2023.1252862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 09/22/2023] [Indexed: 10/31/2023]
Abstract
The subtropical regions in China are prone to recurrent summer droughts induced by the Western Pacific Subtropical High-Pressure, which has induced the death of tens of millions of culms of Moso bamboo (Phyllostachys edulis (Carriere) J. Houzeau), a widely distributed giant bamboo with high economic and ecological values. In the future, the intensity and frequency of the summer drought are projected to increase in these areas due to global climate change, which may lead to significant age-specific mortality of Moso bamboo. So far, it is still unclear about the age-specific response mechanisms of hydraulic traits and carbon balance of Moso bamboo when it is suffering to an ongoing summer drought. This study aimed to investigate the hydraulic and photosynthetic responses of newly sprouted (1 year old) and established (2-5 years old) culms of Moso bamboo to summer drought, which was manipulated by throughfall reduction in Lin'an of Zhejiang. The results showed that both newly sprouted and established culms had a gradually weakening hydraulic conductivity and photosynthesis during the whole drought process. In the early stage of the manipulated drought, the established culms had more loss of hydraulic conductivity than the newly sprouted culms. However, the newly sprouted culms had significant more loss of hydraulic conductivity and lower photosynthetic rates and stomatal conductance in the middle and late stages of the manipulated drought. The results suggest that the newly sprouted culms were more susceptible to summer drought than established culms due to the combined effects of hydraulic damage and photosynthetic restriction, explaining why the newly sprouted culms have higher mortality than elder culms when subjected to extreme drought. These findings provided insights into the mechanisms of Moso bamboo's age-specific drought-induced mortality, which will help for the anti-drought management of bamboo.
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Affiliation(s)
- Xin Zhang
- State Key Laboratory of Subtropical Silvilculture, Zhejiang A&F University, Lin’an, Zhejiang, China
| | - Chazi Tong
- State Key Laboratory of Subtropical Silvilculture, Zhejiang A&F University, Lin’an, Zhejiang, China
| | - Dongming Fang
- State Key Laboratory of Subtropical Silvilculture, Zhejiang A&F University, Lin’an, Zhejiang, China
- College of Horticulture, Jiyang College of Zhejiang Agriculture and Forestry University, Zhuji, Zhejiang, China
| | - Tingting Mei
- State Key Laboratory of Subtropical Silvilculture, Zhejiang A&F University, Lin’an, Zhejiang, China
| | - Yan Li
- State Key Laboratory of Subtropical Silvilculture, Zhejiang A&F University, Lin’an, Zhejiang, China
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Quetin GR, Anderegg LDL, Boving I, Anderegg WRL, Trugman AT. Observed forest trait velocities have not kept pace with hydraulic stress from climate change. GLOBAL CHANGE BIOLOGY 2023; 29:5415-5428. [PMID: 37421154 DOI: 10.1111/gcb.16847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 05/25/2023] [Indexed: 07/09/2023]
Abstract
The extent to which future climate change will increase forest stress and the amount to which species and forest ecosystems can acclimate or adapt to increased stress is a major unknown. We used high-resolution maps of hydraulic traits representing the diversity in tree drought tolerance across the United States, a hydraulically enabled tree model, and forest inventory observations of demographic shifts to quantify the ability for within-species acclimation and between-species range shifts to mediate climate stress. We found that forests are likely to experience increases in both acute and chronic hydraulic stress with climate change. Based on current species distributions, regional hydraulic trait diversity was sufficient to buffer against increased stress in 88% of forested areas. However, observed trait velocities in 81% of forested areas are not keeping up with the rate required to ameliorate projected future stress without leaf area acclimation.
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Affiliation(s)
- G R Quetin
- Department of Geography, University of California, Santa Barbara, California, USA
| | - L D L Anderegg
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California, USA
| | - I Boving
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California, USA
| | - W R L Anderegg
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - A T Trugman
- Department of Geography, University of California, Santa Barbara, California, USA
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4
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Pfeilsticker TR, Jones RC, Steane DA, Vaillancourt RE, Potts BM. Molecular insights into the dynamics of species invasion by hybridisation in Tasmanian eucalypts. Mol Ecol 2023; 32:2913-2929. [PMID: 36807951 DOI: 10.1111/mec.16892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/26/2022] [Accepted: 01/26/2023] [Indexed: 02/22/2023]
Abstract
In plants where seed dispersal is limited compared with pollen dispersal, hybridisation may enhance gene exchange and species dispersal. We provide genetic evidence of hybridisation contributing to the expansion of the rare Eucalyptus risdonii into the range of the widespread Eucalyptus amygdalina. These closely related tree species are morphologically distinct, and observations suggest that natural hybrids occur along their distribution boundaries and as isolated trees or in small patches within the range of E. amygdalina. Hybrid phenotypes occur outside the range of normal dispersal for E. risdonii seed, yet in some hybrid patches small individuals resembling E. risdonii occur and are hypothesised to be a result of backcrossing. Using 3362 genome-wide SNPs assessed from 97 individuals of E. risdonii and E. amygdalina and 171 hybrid trees, we show that (i) isolated hybrids match the genotypes expected of F1 /F2 hybrids, (ii) there is a continuum in the genetic composition among the isolated hybrid patches from patches dominated by F1 /F2 -like genotypes to those dominated by E. risdonii-backcross genotypes, and (iii) the E. risdonii-like phenotypes in the isolated hybrid patches are most-closely related to proximal larger hybrids. These results suggest that the E. risdonii phenotype has been resurrected in isolated hybrid patches established from pollen dispersal, providing the first steps in its invasion of suitable habitat by long-distance pollen dispersal and complete introgressive displacement of E. amygdalina. Such expansion accords with the population demographics, common garden performance data, and climate modelling which favours E. risdonii and highlights a role of interspecific hybridisation in climate change adaptation and species expansion.
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Affiliation(s)
- Thais R Pfeilsticker
- School of Natural Sciences and ARC Training Centre for Forest Value, University of Tasmania, Hobart, Tasmania, Australia
| | - Rebecca C Jones
- School of Natural Sciences and ARC Training Centre for Forest Value, University of Tasmania, Hobart, Tasmania, Australia
| | - Dorothy A Steane
- School of Natural Sciences and ARC Training Centre for Forest Value, University of Tasmania, Hobart, Tasmania, Australia
| | - René E Vaillancourt
- School of Natural Sciences and ARC Training Centre for Forest Value, University of Tasmania, Hobart, Tasmania, Australia
| | - Brad M Potts
- School of Natural Sciences and ARC Training Centre for Forest Value, University of Tasmania, Hobart, Tasmania, Australia
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Drake-Schultheis L, D'Antonio CM, Oono R. Patterns and Distribution of Botryosphaeriaceae Fungi Related to Dieback in Big Berry Manzanita. PHYTOPATHOLOGY 2022; 112:2341-2350. [PMID: 35731020 DOI: 10.1094/phyto-02-22-0044-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Dieback and mortality in wildland plant species due to climate change have been on the rise in recent decades, and latent fungal pathogens might play a significant role in these events. During a severe multiyear drought, canopy dieback associated with latent pathogens in the Botryosphaeriaceae (Bot) family was observed in stands of a dominant shrub species, big berry manzanita (Arctostaphylos glauca), across chaparral landscapes in California. These fungi are significant pathogens of woody agricultural species, especially in hosts experiencing stress, and have become a threat to economically important crops worldwide. However, little is known regarding their occurrence, distribution, and impact in wildland systems. We conducted a field survey of 300 A. glauca shrubs across an elevational gradient to identify Bot species infection as it relates to (i) A. glauca dieback severity and (ii) landscape variables associated with plant drought stress. Our results show that Bots are widely infecting A. glauca across the landscape, and there is a significant correlation between elevation and dieback severity. Dieback severity was significantly higher at lower elevations, suggesting that infected shrubs at lower elevations are at greater risk than those at higher elevations. Furthermore, two Bot species, Neofusicoccum australe and Botryosphaeria dothidea, were most frequently isolated, with N. australe being the most common and, based on haplotype analysis, likely the most recently introduced of the two. Our results confirm the wide distribution of latent Bot fungi in a wild shrubland system and provide valuable insight into areas of greatest risk for future shrub dieback and mortality. These findings could be particularly useful for informing future wildlands management strategies with regard to introduced latent pathogens.
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Affiliation(s)
- Laura Drake-Schultheis
- Ecology, Evolution, and Marine Biology Department, University of California, Santa Barbara, CA 93106
- Life Sciences Department, Westmont College, Santa Barbara, CA 93108
| | - Carla M D'Antonio
- Ecology, Evolution, and Marine Biology Department, University of California, Santa Barbara, CA 93106
| | - Ryoko Oono
- Ecology, Evolution, and Marine Biology Department, University of California, Santa Barbara, CA 93106
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Kerr KL, Anderegg LDL, Zenes N, Anderegg WRL. Quantifying within‐species trait variation in space and time reveals limits to trait‐mediated drought response. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Kelly L. Kerr
- School of Biological Sciences University of Utah Salt Lake City UT USA
| | - Leander D. L. Anderegg
- Department of Ecology, Evolution, and Marine Biology University of California Santa Barbara Santa Barbara CA USA
| | - Nicole Zenes
- School of Biological Sciences University of Utah Salt Lake City UT USA
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Li X, Xi B, Wu X, Choat B, Feng J, Jiang M, Tissue D. Unlocking Drought-Induced Tree Mortality: Physiological Mechanisms to Modeling. FRONTIERS IN PLANT SCIENCE 2022; 13:835921. [PMID: 35444681 PMCID: PMC9015645 DOI: 10.3389/fpls.2022.835921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
Drought-related tree mortality has become a major concern worldwide due to its pronounced negative impacts on the functioning and sustainability of forest ecosystems. However, our ability to identify the species that are most vulnerable to drought, and to pinpoint the spatial and temporal patterns of mortality events, is still limited. Model is useful tools to capture the dynamics of vegetation at spatiotemporal scales, yet contemporary land surface models (LSMs) are often incapable of predicting the response of vegetation to environmental perturbations with sufficient accuracy, especially under stressful conditions such as drought. Significant progress has been made regarding the physiological mechanisms underpinning plant drought response in the past decade, and plant hydraulic dysfunction has emerged as a key determinant for tree death due to water shortage. The identification of pivotal physiological events and relevant plant traits may facilitate forecasting tree mortality through a mechanistic approach, with improved precision. In this review, we (1) summarize current understanding of physiological mechanisms leading to tree death, (2) describe the functionality of key hydraulic traits that are involved in the process of hydraulic dysfunction, and (3) outline their roles in improving the representation of hydraulic function in LSMs. We urge potential future research on detailed hydraulic processes under drought, pinpointing corresponding functional traits, as well as understanding traits variation across and within species, for a better representation of drought-induced tree mortality in models.
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Affiliation(s)
- Ximeng Li
- College of Life and Environmental Science, Minzu University of China, Beijing, China
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Benye Xi
- Ministry of Education Key Laboratory of Silviculture and Conservation, Beijing Forestry University, Beijing, China
| | - Xiuchen Wu
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Jinchao Feng
- College of Life and Environmental Science, Minzu University of China, Beijing, China
| | - Mingkai Jiang
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - David Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- Global Centre for Land-based Innovation, Western Sydney University, Richmond, NSW, Australia
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Krivak-Tetley FE, Sullivan-Stack J, Garnas JR, Zylstra KE, Höger LO, Lombardero MJ, Liebhold AM, Ayres MP. Demography of an invading forest insect reunited with hosts and parasitoids from its native range. NEOBIOTA 2022. [DOI: 10.3897/neobiota.72.75392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The Sirex woodwasp Sirex noctilio Fabricius (Hymenoptera: Siricidae), a widespread invasive pest of pines in the Southern Hemisphere, was first detected in North America in 2004. This study assessed the impacts of life history traits, host resistance and species interactions on the demography of S. noctilio in New York, Pennsylvania and Vermont, then compared key metrics to those found in the native range in Galicia, Spain. Many trees naturally attacked by S. noctilio in North America produced no adult woodwasps, with 5 of 38 infested trees (13%) sampled across six sites yielding 64% of emerging insects. Reproductive success was highest in the introduced host scots pine, Pinus sylvestris, but native red pine, Pinus resinosa, produced larger insects. Sirex noctilio required one or sometimes two years to develop and sex ratios were male biased, 1:2.98 ♀:♂. Body size and fecundity were highly variable, but generally lower than observed in non-native populations in the Southern Hemisphere. Hymenopteran parasitoids killed approximately 20% of S. noctilio larvae and 63% of emerging adults were colonized by the parasitic nematode Deladenus siricidicola, although no nematodes entered eggs. Demographic models suggested that S. noctilio in the northeastern USA have a higher potential for population growth than populations in the native range: estimated finite factor of increase, λ, was 4.17–4.52 (depending on tree species colonized), compared to λ = 1.57 in Spain.
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Keen RM, Voelker SL, Wang SYS, Bentz BJ, Goulden ML, Dangerfield CR, Reed CC, Hood SM, Csank AZ, Dawson TE, Merschel AG, Still CJ. Changes in tree drought sensitivity provided early warning signals to the California drought and forest mortality event. GLOBAL CHANGE BIOLOGY 2022; 28:1119-1132. [PMID: 34735729 DOI: 10.1111/gcb.15973] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/05/2021] [Indexed: 06/13/2023]
Abstract
Climate warming in recent decades has negatively impacted forest health in the western United States. Here, we report on potential early warning signals (EWS) for drought-related mortality derived from measurements of tree-ring growth (ring width index; RWI) and carbon isotope discrimination (∆13 C), primarily focused on ponderosa pine (Pinus ponderosa). Sampling was conducted in the southern Sierra Nevada Mountains, near the epicenter of drought severity and mortality associated with the 2012-2015 California drought and concurrent outbreak of western pine beetle (Dendroctonus brevicomis). At this site, we found that widespread mortality was presaged by five decades of increasing sensitivity (i.e., increased explained variation) of both tree growth and ∆13 C to Palmer Drought Severity Index (PDSI). We hypothesized that increasing sensitivity of tree growth and ∆13 C to hydroclimate constitute EWS that indicate an increased likelihood of widespread forest mortality caused by direct and indirect effects of drought. We then tested these EWS in additional ponderosa pine-dominated forests that experienced varying mortality rates associated with the same California drought event. In general, drier sites showed increasing sensitivity of RWI to PDSI over the last century, as well as higher mortality following the California drought event compared to wetter sites. Two sites displayed evidence that thinning or fire events that reduced stand basal area effectively reversed the trend of increasing hydroclimate sensitivity. These comparisons indicate that reducing competition for soil water and/or decreasing bark beetle host tree density via forest management-particularly in drier regions-may buffer these forests against drought stress and associated mortality risk. EWS such as these could provide land managers more time to mitigate the extent or severity of forest mortality in advance of droughts. Substantial efforts at deploying additional dendrochronological research in concert with remote sensing and forest modeling will aid in forecasting of forest responses to continued climate warming.
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Affiliation(s)
- Rachel M Keen
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Steven L Voelker
- College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan, USA
| | - S-Y Simon Wang
- Department of Plants, Soils and Climate, Utah State University, Logan, Utah, USA
| | - Barbara J Bentz
- USDA Forest Service, Rocky Mountain Research Station, Logan, Utah, USA
| | - Michael L Goulden
- Department of Earth System Science, University of California, Irvine, California, USA
| | - Cody R Dangerfield
- Department of Wildland Resources, Utah State University, Logan, Utah, USA
| | - Charlotte C Reed
- Fire Sciences Laboratory, USDA Forest Service, Rocky Mountain Research Station, Missoula, Montana, USA
| | - Sharon M Hood
- Fire Sciences Laboratory, USDA Forest Service, Rocky Mountain Research Station, Missoula, Montana, USA
| | - Adam Z Csank
- Department of Geography, University of Nevada, Reno, Nevada, USA
| | - Todd E Dawson
- Department of Environmental Science, Policy & Management, University of California, Berkeley, California, USA
| | - Andrew G Merschel
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, Oregon, USA
| | - Christopher J Still
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, Oregon, USA
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Marchand W, Girardin MP, Hartmann H, Lévesque M, Gauthier S, Bergeron Y. Contrasting life-history traits of black spruce and jack pine influence their physiological response to drought and growth recovery in northeastern boreal Canada. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 794:148514. [PMID: 34218146 DOI: 10.1016/j.scitotenv.2021.148514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/09/2021] [Accepted: 06/14/2021] [Indexed: 06/13/2023]
Abstract
An increase in frequency, intensity and duration of drought events affects forested ecosystems. Trees react to these changes by adjusting stomatal conductance to maximize the trade-off between carbon gains and water losses. A better understanding of the consequences of these drought-induced physiological adjustments for tree growth could help inferring future productivity potentials of boreal forests. Here, we used samples from a forest inventory network in Canada where a decline in growth rates of black spruce (Picea mariana (Mill.) B.S.P.) and jack pine (Pinus banksiana Lamb.) occurred in 1988-1992, an exceptionally dry period, to verify if this growth decline resulted from physiological adjustments of trees to drought. We measured carbon and oxygen isotope ratios in growth rings of 95 spruces and 49 pines spanning 1985-1993. We used 13C discrimination (Δ13C) and 18O enrichment (Δ18O) as proxies for intrinsic water use efficiency and stomatal conductance, respectively. We studied how inter-annual variability in isotopic signals was linked to climate moisture index, vapor pressure deficit and annual snowfall amount. We found significantly lower Δ13C values over 1988-1990, and significantly higher Δ18O values in 1988-1989 and 1991 compared to the 1985-1993 averages. We also observed that a low climatic water balance and a high vapor pressure deficit were linked with low Δ13C and high Δ18O in the two study species, in parallel with low growth rates. The latter effect persisted into the year following drought for black spruce, but not for jack pine. These findings highlight that small differences in physiological parameters between species could translate into large differences in post-drought recovery. The stronger and longer lasting impact on black spruce compared to jack pine suggests a less efficient carbon use and a lower acclimation potential to future warmer and drier climate conditions.
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Affiliation(s)
- William Marchand
- Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, succ. Centre-ville, Montréal, QC H3C 3P8, Canada; Department of Forest Ecology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Kamýcká 129, Praha 6 - Suchdol 165 00, Czech Republic; Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S, P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada.
| | - Martin P Girardin
- Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, succ. Centre-ville, Montréal, QC H3C 3P8, Canada; Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S, P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada
| | - Henrik Hartmann
- Max-Planck Institute for Biogeochemistry, Department of Biogeochemical Processes, Hans-Knöll Str. 10, 07745 Jena, Germany
| | - Mathieu Lévesque
- Forest Management/Silviculture Group, Institute of Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland
| | - Sylvie Gauthier
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S, P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada; Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, succ. Centre-ville, Montréal, QC H3C 3P8, Canada
| | - Yves Bergeron
- Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, succ. Centre-ville, Montréal, QC H3C 3P8, Canada; Institut de recherche sur les forêts, Université du Québec en Abitibi-Témiscamingue, 445 boul. de l'Université, Rouyn-Noranda, QC J9X 5E4, Canada
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11
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Vitali V, Klesse S, Weigt R, Treydte K, Frank D, Saurer M, Siegwolf RTW. High-frequency stable isotope signals in uneven-aged forests as proxy for physiological responses to climate in Central Europe. TREE PHYSIOLOGY 2021; 41:2046-2062. [PMID: 33960372 DOI: 10.1093/treephys/tpab062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 04/26/2021] [Indexed: 06/12/2023]
Abstract
Picea abies (L.) Karst. and Fagus sylvatica (L.) are important tree species in Europe, and the foreseen increase in temperature and vapour pressure deficit (VPD) could increase the vulnerability of these species. However, their physiological performance under climate change at temperate and productive sites is not yet fully understood, especially in uneven-aged stands. Therefore, we investigated tree-ring width and stable isotope chronologies (δ13C/δ18O) of these two species at 10 sites along a climate gradient in Central Europe. In these uneven-aged stands, we compared the year-to-year variability of dominant and suppressed trees for the last 80 years in relation to the sites' spatial distribution and climate. δ18O and δ13C were generally consistent across sites and species, showing high sensitivity to summer VPD, whereas climate correlations with radial growth varied much more and depended on mean local climate. We found no significant differences between dominant and suppressed trees in the response of stable isotope ratios to climate variability, especially within the annual high-frequency signals. In addition, we observed a strikingly high coherence of the high-frequency δ18O variations across long distances with significant correlations above 1500 km, whereas the spatial agreement of δ13C variations was weaker (~700 km). We applied a dual-isotope approach that is based on known theoretical understanding of isotope fractionations to translate the observed changes into physiological components, mainly photosynthetic assimilation rate and stomatal conductance. When separating the chronologies in two time windows and investigating the shifts in isotopes ratios, a significant enrichment of either or both isotope ratios over the last decades can be observed. These results, translated by the dual-isotope approach, indicate a general climate-driven decrease in stomatal conductance. This improved understanding of the physiological mechanisms controlling the short-term variation of the isotopic signature will help to define the performance of these tree species under future climate.
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Affiliation(s)
- Valentina Vitali
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
| | - Stefan Klesse
- Swiss Forest Protection, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
- Forest Resources and Management, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
| | - Rosemarie Weigt
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
- Ecosystem Fluxes Group, Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Kerstin Treydte
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
| | - David Frank
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
- Laboratory of Tree-Ring Research, University of Arizona, 1215 E Lowell St, Tucson, AZ 85721, USA
| | - Matthias Saurer
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
- Ecosystem Fluxes Group, Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Rolf T W Siegwolf
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
- Ecosystem Fluxes Group, Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
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12
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The Role of Aging and Wind in Inducing Death and/or Growth Reduction in Korean Fir (Abies Koreana Wilson) on Mt. Halla, Korea. ATMOSPHERE 2021. [DOI: 10.3390/atmos12091135] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The purpose of this study was to investigate the role of strong winds and aging in the death and/or decline in the growth of Korean fir on Mt. Halla in Korea. Bangeoreum (BA-S), Jindalrebat (JD-E), and Youngsil (YS-W) on the southern, eastern, and western slopes of Mt. Halla (ca. 1600 and 1700 m a.s.l.) were selected for the study. The site chronologies were established using more than 10 living Korean firs at each site. Additionally, to date the years and seasons of death of standing/fallen dead Korean firs, 15/15, 14/15, and 10/10 trees were selected at BA-S, JD-E, and YS-W, respectively. After adjusting the age with the period of growth up to the sampling point, the oldest Korean fir found among the living trees was 114 years old at JD-E and the oldest fir among the dead trees was 131 years old at JD-E. Besides this, most of the trees at BA-S and JD-E were found to have died between 2008 and 2015, and at irregular intervals between 1976 and 2013 at YS-W. Also, the maximum number of trees, that is, 62.7% died between spring and summer, followed by 20.9% between summer and autumn, and 16.4% between autumn of the current year and spring of the following year. Abrupt growth reductions occurred at BA-S and JD-E, and have become more significant in recent years, whereas at YS-W, the abrupt growth reduction and recovery occur in a cyclic order. The intensity and frequency of the typhoons increased from 2012, and this trend was in-line with the increased number of abrupt growth reductions at BA-S and JD-E. Therefore, the typhoons of 2012 are considered as the most likely influencing factor in death and/or growth reduction in Korean firs. In contrast, the decline in the growth of the Korean firs located on the windward slope (YS-W) showed a relationship with winds stronger than 25–33 m/s.
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13
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Liu Q, Peng C, Schneider R, Cyr D, Liu Z, Zhou X, Kneeshaw D. TRIPLEX-Mortality model for simulating drought-induced tree mortality in boreal forests: Model development and evaluation. Ecol Modell 2021. [DOI: 10.1016/j.ecolmodel.2021.109652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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14
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Continent-wide synthesis of the long-term population dynamics of quaking aspen in the face of accelerating human impacts. Oecologia 2021; 197:25-42. [PMID: 34365517 DOI: 10.1007/s00442-021-05013-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 08/03/2021] [Indexed: 10/20/2022]
Abstract
In recent decades, climate change has disrupted forest functioning by promoting large-scale mortality events, declines in productivity and reduced regeneration. Understanding the temporal dynamics and spatial extent of these changes is critical given the essential ecosystem services provided by forests. As the most widespread tree species in North America, quaking aspen (Populus tremuloides) is well suited for studying the dynamics of tree populations during a period of unprecedented climate change. Synthesizing continent-wide data, we show that mortality rates of mature aspen stems have increased over the past two-to-three decades, while relative gains in aspen basal area have decreased during the same period. Patterns were pervasive across multiple stand size classes and composition types in western North America biomes, suggesting that trends in demographic rates were not simply a reflection of stand development and succession. Our review of the literature revealed that increased aspen mortality and reduced growth rates were most often associated with hotter, drier conditions, whereas reduced recruitment was most often associated with herbivory. Furthermore, interactions between climate and competition, as well as climate and insect herbivory, had important, context-dependent effects on mortality and growth, respectively. Our analyses of aspen across its entire geographic range indicate that this important tree species is experiencing substantial increases in mortality and decreases in population growth rates across multiple biomes. If such trends are not accompanied by increased recruitment, we expect that the reduced dominance of aspen in forests will lead to major declines in the many essential ecosystem services it provides.
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15
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Age-Based Survival Analysis of Coniferous and Broad-Leaved Trees: A Case Study of Preserved Forests in Northern Japan. FORESTS 2021. [DOI: 10.3390/f12081014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Scientifically sound methods are essential to estimate the survival of trees, as they can substantially support sustainable management of natural forest resources. Tree mortality assessments have mainly been based on forest inventories and are mostly limited to planted forests; few studies have conducted age-based survival analyses in natural forests. We performed survival analyses of individual tree populations in natural forest stands to evaluate differences in the survival of two coniferous species (Abies sachalinensis (F. Schmidt) Mast. and Picea jezoensis var. microsperma) and all broad-leaved species. We used tree rings and census data from four preserved permanent plots in pan-mixed and sub-boreal natural forests obtained over 30 years (1989–2019). All living trees (diameter at breast height ≥ 5 cm in 1989) were targeted to identify tree ages using a Resistograph. Periodical tree age data, for a 10-year age class, were obtained during three consecutive observation periods. Mortality and recruitment changes were recorded to analyze multi-temporal age distributions and mean lifetimes. Non-parametric survival analyses revealed a multi-modal age distribution and exponential shapes. There were no significant differences among survival probabilities of species in different periods, except for broad-leaved species, which had longer mean lifetimes in each period than coniferous species. The estimated practical mean lifetime and diameter at breast height values of each coniferous and broad-leaved tree can be applied as an early identification system for trees likely to die to facilitate the Stand-based Silvicultural Management System of the University of Tokyo Hokkaido Forest. However, the survival probabilities estimated in this study should be used carefully in long-term forest dynamic predictions because the analysis did not include the effects of catastrophic disturbances, which might significantly influence forests. The mortality patterns and survival probabilities reported in this study are valuable for understanding the stand dynamics of natural forests associated with the mortality of individual tree populations.
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16
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Manea A, Tabassum S, Leishman MR. Eucalyptus
species maintain secondary metabolite production under water stress conditions at the expense of growth. AUSTRAL ECOL 2021. [DOI: 10.1111/aec.13035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Anthony Manea
- Department of Biological Sciences Macquarie University North Ryde New South Wales 2109 Australia
| | - Samiya Tabassum
- Department of Biological Sciences Macquarie University North Ryde New South Wales 2109 Australia
| | - Michelle R. Leishman
- Department of Biological Sciences Macquarie University North Ryde New South Wales 2109 Australia
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17
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Gattmann M, Birami B, Nadal Sala D, Ruehr NK. Dying by drying: Timing of physiological stress thresholds related to tree death is not significantly altered by highly elevated CO 2. PLANT, CELL & ENVIRONMENT 2021; 44:356-370. [PMID: 33150582 DOI: 10.1111/pce.13937] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 10/13/2020] [Indexed: 05/03/2023]
Abstract
Drought-induced tree mortality is expected to occur more frequently under predicted climate change. However, the extent of a possibly mitigating effect of simultaneously rising atmospheric [CO2 ] on stress thresholds leading to tree death is not fully understood, yet. Here, we studied the drought response, the time until critical stress thresholds were reached and mortality occurrence of Pinus halepensis (Miller). In order to observe a large potential benefit from eCO2 , the seedlings were grown with ample of water and nutrient supply under either highly elevated [CO2 ] (eCO2 , c. 936 ppm) or ambient (aCO2 , c. 407 ppm) during 2 years. The subsequent exposure to a fast or a slow lethal drought was monitored using whole-tree gas exchange chambers, measured leaf water potential and non-structural carbohydrates. Using logistic regressions to derive probabilities for physiological parameters to reach critical drought stress thresholds, indicated a longer period for halving needle starch storage under eCO2 than aCO2 . Stomatal closure, turgor loss, the duration until the daily tree C balance turned negative, leaf water potential at thresholds and time-of-death were unaffected by eCO2 . Overall, our study provides for the first-time insights into the chronological interplay of physiological drought thresholds under long-term acclimation to elevated [CO2 ].
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Affiliation(s)
- Marielle Gattmann
- Institute of Meteorology and Climate Research - Atmospheric Environmental Research, Karlsruhe Institute of Technology KIT, Garmisch-Partenkirchen, Germany
| | - Benjamin Birami
- Institute of Meteorology and Climate Research - Atmospheric Environmental Research, Karlsruhe Institute of Technology KIT, Garmisch-Partenkirchen, Germany
| | - Daniel Nadal Sala
- Institute of Meteorology and Climate Research - Atmospheric Environmental Research, Karlsruhe Institute of Technology KIT, Garmisch-Partenkirchen, Germany
| | - Nadine Katrin Ruehr
- Institute of Meteorology and Climate Research - Atmospheric Environmental Research, Karlsruhe Institute of Technology KIT, Garmisch-Partenkirchen, Germany
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18
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Comparison of Selected Terramechanical Test Procedures and Cartographic Indices to Predict Rutting Caused by Machine Traffic during a Cut-to-Length Thinning Operation. FORESTS 2021. [DOI: 10.3390/f12020113] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Timber harvesting operations using heavy forest machinery frequently results in severe soil compaction and displacement, threatening sustainable forest management. An accurate prediction of trafficability, considering actual operating conditions, minimizes these impacts and can be facilitated by various predictive tools. Within this study, we validated the accuracy of four terramechanical parameters, including Cone Index (MPa, Penetrologger), penetration depth (cm, Penetrologger), cone penetration (cm blow−1, dual-mass dynamic cone penetrometer) and shear strength (kPa, vane meter), and additionally two cartographic indices (topographic wetness index and depth-to-water). Measurements applying the four terramechanical approaches were performed at 47 transects along newly assigned machine operating trails in two broadleaved dominated mixed stands. After the CTL thinning operation was completed, measurement results and cartographic indices were correlated against rut depth. Under the rather dry soil conditions (29 ± 9 vol%), total rut depth ranged between 2.2 and 11.6 cm, and was clearly predicted by rut depth after a single pass of the harvester, which was used for further validations. The results indicated the easy-to-measure penetration depth as the most accurate approach to predict rut depth, considering coefficients of correlation (rP = 0.44). Moreover, cone penetration (rP = 0.34) provided reliable results. Surprisingly, no response between rut depth and Cone Index was observed, although it is commonly used to assess trafficability. The relatively low moisture conditions probably inhibited a correlation between rutting and moisture content. Consistently, cartographic indices could not be used to predict rutting. Rut depth after the harvester pass was a reliable predictor for total rut depth after 2–5 passes (rP = 0.50). Rarely used parameters, such as cone penetration or shear strength, outcompeted the highly reputed Cone Index, emphasizing further investigations of applied tools.
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19
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Keen RM, Voelker SL, Bentz BJ, Wang SYS, Ferrell R. Stronger influence of growth rate than severity of drought stress on mortality of large ponderosa pines during the 2012-2015 California drought. Oecologia 2020; 194:359-370. [PMID: 33030569 DOI: 10.1007/s00442-020-04771-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 09/25/2020] [Indexed: 11/29/2022]
Abstract
Forests in the western United States are being subject to more frequent and severe drought events as the climate warms. The 2012-2015 California drought is a recent example, whereby drought stress was exacerbated by a landscape-scale outbreak of western pine beetle (Dendroctonus brevicomis) and resulted in widespread mortality of dominant canopy species including ponderosa pine (Pinus ponderosa). In this study, we compared pairs of large surviving and beetle-killed ponderosa pines following the California drought in the southern Sierra Nevadas to evaluate physiological characteristics related to survival. Inter-annual growth rates and tree-ring stable isotopes (∆13C and δ18O) were utilized to compare severity of drought stress and climate sensitivity in ponderosa pines that survived and those that were killed by western pine beetle. Compared to beetle-killed trees, surviving trees had higher growth rates and grew in plots with lower ponderosa pine basal area. However, there were no detectable differences in tree-ring ∆13C, δ18O, or stable isotope sensitivity to drought-related meteorological variables. These results indicate that differences in severity of drought stress had little influence on local, inter-tree differences in growth rate and survival of large ponderosa pines during this drought event. Many previous studies have shown that large trees are more likely to be attacked and killed by bark beetles compared to small trees. Our results further suggest that among large ponderosa pines, those that were more resistant to drought stress and bark beetle attacks were in the upper echelon of growth rates among trees within a stand and across the landscape.
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Affiliation(s)
- Rachel M Keen
- Division of Biology, Kansas State University, Manhattan, KS, USA.
| | - Steve L Voelker
- Department of Environmental and Forest Biology, SUNY ESF, Syracuse, NY, USA
| | - Barbara J Bentz
- USDA Forest Service, Rocky Mountain Research Station, Logan, UT, USA
| | - S-Y Simon Wang
- Department of Plants, Soils and Climate, Utah State University, Logan, UT, USA
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20
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Abstract
The importance of tree genetic variability in the ability of forests to respond and adapt to environmental changes is crucial in forest management and conservation. Along with genetics, recent advances have highlighted “epigenetics” as an emerging and promising field of research for the understanding of tree phenotypic plasticity and adaptive responses. In this paper, we review recent advances in this emerging field and their potential applications for tree researchers and breeders, as well as for forest managers. First, we present the basics of epigenetics in plants before discussing its potential for trees. We then propose a bibliometric and overview of the literature on epigenetics in trees, including recent advances on tree priming. Lastly, we outline the promises of epigenetics for forest research and management, along with current gaps and future challenges. Research in epigenetics could use highly diverse paths to help forests adapt to global change by eliciting different innovative silvicultural approaches for natural- and artificial-based forest management.
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21
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Smith‐Martin CM, Skelton RP, Johnson KM, Lucani C, Brodribb TJ. Lack of vulnerability segmentation among woody species in a diverse dry sclerophyll woodland community. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13519] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Chris M. Smith‐Martin
- Department of Ecology, Evolution and Evolutionary Biology Columbia University New York NY USA
| | - Robert Paul Skelton
- South African Environmental Observation NetworkKirstenbosch Botanical Gardens Cape Town South Africa
| | - Kate M. Johnson
- School of Biological Sciences University of Tasmania Hobart TAS Australia
| | - Christopher Lucani
- School of Biological Sciences University of Tasmania Hobart TAS Australia
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22
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Cranston BM, Powers BF, Macinnis-Ng C. Inexpensive throughfall exclusion experiment for single large trees. APPLICATIONS IN PLANT SCIENCES 2020; 8:e11325. [PMID: 32110504 PMCID: PMC7035431 DOI: 10.1002/aps3.11325] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 10/26/2019] [Indexed: 05/18/2023]
Abstract
PREMISE Drought-induced tree mortality is an emergent threat to forests worldwide, particularly to large trees. Drought-manipulation experiments involving throughfall exclusion (TFE) tend to focus on large plots that can be expensive to establish and maintain and may be unsuitable for large trees or indigenous forests. We set out to establish a relatively inexpensive TFE method in a natural forest with large trees. METHODS We designed a novel TFE method and installed it in the Waitākere Range of West Auckland, New Zealand, to study the southern conifer kauri (Agathis australis) under long-term simulated drought. We measured fluxes of water (sap flow) and carbon (stem increment and litterfall) as indicators of drought effects. RESULTS Throughfall was cut off to a 22.25-m2 area around individual boles, causing reduced soil moisture and reduced sap flow in droughted trees. DISCUSSION Our new TFE method centered on individual, large trees in native forest and is highly customizable to fit other forest and species types. It can be used to assess physiological responses to drought of individual trees independent of stem size.
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Affiliation(s)
- Benjamin M Cranston
- School of Biological Sciences The University of Auckland Private Bag 92019 Auckland Mail Center Auckland 1142 New Zealand
| | - Breanna F Powers
- School of the Environment The University of Auckland Private Bag 92019 Auckland Mail Center Auckland 1142 New Zealand
- Te Pūnaha Matatini The University of Auckland Private Bag 92019 Auckland Mail Center Auckland 1142 New Zealand
- Present address: Department of Biological Sciences Boise State University 1910 University Drive Boise Idaho 83725 USA
| | - Cate Macinnis-Ng
- School of Biological Sciences The University of Auckland Private Bag 92019 Auckland Mail Center Auckland 1142 New Zealand
- Te Pūnaha Matatini The University of Auckland Private Bag 92019 Auckland Mail Center Auckland 1142 New Zealand
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23
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Forest Contribution to Climate Change Mitigation: Management Oriented to Carbon Capture and Storage. CLIMATE 2020. [DOI: 10.3390/cli8020021] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Today, climate change is assumed by many researchers and scholars as a certainty and is presented as the biggest challenge humanity has ever faced. It is commonly accepted that anthropogenic greenhouse gas emissions are the main cause that is accelerating the process. Therefore, it is urgent to find solutions to mitigate climate change, mainly because the intense effects have already been felt, in many cases in the form of the occurrence of extremely violent weather events. Forests are undoubtedly one of the most effective and easiest ways to provide the function of carbon sinks. However, it is essential and convenient to analyze the permanence time of this carbon in forests, because this permanence time depends directly on the forest management model used. This article aims to analyze forest management models from the perspective of carbon residence time in temperate forests, dividing the models into three types, namely carbon conservation models, carbon storage models, and carbon substitution models, according to their ability to contribute to functioning as carbon sinks, thereby contributing to the mitigation of climate change.
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24
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Schwendenmann L, Michalzik B. Dissolved and particulate carbon and nitrogen fluxes along a Phytophthora agathidicida infection gradient in a kauri (Agathis australis) dominated forest. FUNGAL ECOL 2019. [DOI: 10.1016/j.funeco.2019.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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25
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Anderegg WRL, Anderegg LDL, Kerr KL, Trugman AT. Widespread drought-induced tree mortality at dry range edges indicates that climate stress exceeds species' compensating mechanisms. GLOBAL CHANGE BIOLOGY 2019; 25:3793-3802. [PMID: 31323157 DOI: 10.1111/gcb.14771] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 07/01/2019] [Accepted: 07/02/2019] [Indexed: 06/10/2023]
Abstract
Drought-induced tree mortality is projected to increase due to climate change, which will have manifold ecological and societal impacts including the potential to weaken or reverse the terrestrial carbon sink. Predictions of tree mortality remain limited, in large part because within-species variations in ecophysiology due to plasticity or adaptation and ecosystem adjustments could buffer mortality in dry locations. Here, we conduct a meta-analysis of 50 studies spanning >100 woody plant species globally to quantify how populations within species vary in vulnerability to drought mortality and whether functional traits or climate mediate mortality patterns. We find that mortality predominantly occurs in drier populations and this pattern is more pronounced in species with xylem that can tolerate highly negative water potentials, typically considered to be an adaptive trait for dry regions, and species that experience higher variability in water stress. Our results indicate that climate stress has exceeded physiological and ecosystem-level tolerance or compensating mechanisms by triggering extensive mortality at dry range edges and provides a foundation for future mortality projections in empirical distribution and mechanistic vegetation models.
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Affiliation(s)
| | - Leander D L Anderegg
- Department of Global Ecology, Carnegie Institution for Science, Stanford, CA, USA
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, USA
| | - Kelly L Kerr
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Anna T Trugman
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
- Department of Geography, University of California Santa Barbara, Santa Barbara, CA, USA
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26
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Zhang X, Huang X. Human disturbance caused stronger influences on global vegetation change than climate change. PeerJ 2019; 7:e7763. [PMID: 31579623 PMCID: PMC6765362 DOI: 10.7717/peerj.7763] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 08/26/2019] [Indexed: 01/11/2023] Open
Abstract
Global vegetation distribution has been influenced by human disturbance and climate change. The past vegetation changes were studied in numerous studies while few studies had addressed the relative contributions of human disturbance and climate change on vegetation change. To separate the influences of human disturbance and climate change on the vegetation changes, we compared the existing vegetation which indicates the vegetation distribution under human influences with the potential vegetation which reflects the vegetation distribution without human influences. The results showed that climate-induced vegetation changes only occurred in a few grid cells from the period 1982–1996 to the period 1997–2013. Human-induced vegetation changes occurred worldwide, except in the polar and desert regions. About 3% of total vegetation distribution was transformed by human activities from the period 1982–1996 to the period 1997–2013. Human disturbances caused stronger damage to global vegetation change than climate change. Our results indicated that the regions where vegetation experienced both human disturbance and climate change are eco-fragile regions.
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Affiliation(s)
- Xianliang Zhang
- College of Forestry, Hebei Agricultrual University, Baoding, China.,Long-term Forest Silviculture Research Station in Saihanba, Chengde, China
| | - Xuanrui Huang
- College of Forestry, Hebei Agricultrual University, Baoding, China.,Long-term Forest Silviculture Research Station in Saihanba, Chengde, China
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27
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Contrasting Response to Drought and Climate of Planted and Natural Pinus pinaster Aiton Forests in Southern Spain. FORESTS 2019. [DOI: 10.3390/f10070603] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Extreme drought events and increasing aridity are leading to forest decline and tree mortality, particularly in populations near the limits of the species distribution. Therefore, a better understanding of the growth response to drought and climate change could show the vulnerability of forests and enable predictions of future dieback. In this study, we used a dendrochronological approach to assess the response to drought in natural and planted forests of the maritime pine (Pinus pinaster Aiton) located in its southernmost distribution (south of Spain). In addition, we investigated how environmental variables (climatic and site conditions) and structural factors drive radial growth along the biogeographic and ecological gradients. Our results showed contrasting growth responses to drought of natural and planted stands, but these differences were not significant after repeated drought periods. Additionally, we found differences in the climate–growth relationships when comparing more inland sites (wet previous winter and late spring precipitation) and sites located closer to the coast (early spring precipitation). Response functions emphasized the negative effect of defoliation and drought, expressed as the June standard precipitation-evapotranspiration index calculated for the 12-month temporal scale and the mean temperature in the current February, on growth. The strong relationship between climatic variables and growth enabled acceptable results to be obtained in a modeling approach. The study and characterization of this tree species’ response to drought will help to improve the adaptive management of forests under climate change.
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28
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Martinez-Vilalta J, Anderegg WRL, Sapes G, Sala A. Greater focus on water pools may improve our ability to understand and anticipate drought-induced mortality in plants. THE NEW PHYTOLOGIST 2019; 223:22-32. [PMID: 30560995 DOI: 10.1111/nph.15644] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 12/06/2018] [Indexed: 05/23/2023]
Abstract
Drought-induced tree mortality has major impacts on ecosystem carbon and water cycles, and is expected to increase in forests across the globe with climate change. A large body of research in the past decade has advanced our understanding of plant water and carbon relations under drought. However, despite intense research, we still lack generalizable, cross-scale indicators of mortality risk. In this Viewpoint, we propose that a more explicit consideration of water pools could improve our ability to monitor and anticipate mortality risk. Specifically, we focus on the relative water content (RWC), a classic metric in plant water relations, as a potential indicator of mortality risk that is physiologically relevant and integrates different aspects related to hydraulics, stomatal responses and carbon economy under drought. Measures of plant water content are likely to have a strong mechanistic link with mortality and to be integrative, threshold-prone and relatively easy to measure and monitor at large spatial scales, and may complement current mortality metrics based on water potential, loss of hydraulic conductivity and nonstructural carbohydrates. We discuss some of the potential advantages and limitations of these metrics to improve our capacity to monitor and predict drought-induced tree mortality.
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Affiliation(s)
- Jordi Martinez-Vilalta
- CREAF, Cerdanyola del Valles, 08193, Barcelona, Spain
- Universitat Autònoma de Barcelona, Cerdanyola del Valles, 08193, Barcelona, Spain
| | | | - Gerard Sapes
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Anna Sala
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
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29
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Anderegg WRL, Anderegg LDL, Huang CY. Testing early warning metrics for drought-induced tree physiological stress and mortality. GLOBAL CHANGE BIOLOGY 2019; 25:2459-2469. [PMID: 30983066 DOI: 10.1111/gcb.14655] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/25/2019] [Indexed: 06/09/2023]
Abstract
Climate change-driven drought stress has triggered numerous large-scale tree mortality events in recent decades. Advances in mechanistic understanding and prediction are greatly limited by an inability to detect in situ where trees are likely to die in order to take timely measurements and actions. Thus, algorithms of early warning and detection of drought-induced tree stress and mortality could have major scientific and societal benefits. Here, we leverage two consecutive droughts in the southwestern United States to develop and test a set of early warning metrics. Using Landsat satellite data, we constructed early warning metrics from the first drought event. We then tested these metrics' ability to predict spatial patterns in tree physiological stress and mortality from the second drought. To test the broader applicability of these metrics, we also examined a separate drought in the Amazon rainforest. The early warning metrics successfully explained subsequent tree mortality in the second drought in the southwestern US, as well as mortality in the independent drought in tropical forests. The metrics also strongly correlated with spatial patterns in tree hydraulic stress underlying mortality, which provides a strong link between tree physiological stress and remote sensing during the severe drought and indicates that the loss of hydraulic function during drought likely mediated subsequent mortality. Thus, early warning metrics provide a critical foundation for elucidating the physiological mechanisms underpinning tree mortality in mature forests and guiding management responses to these climate-induced disturbances.
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Affiliation(s)
| | - Leander D L Anderegg
- Department of Integrative Biology, UC Berkeley, Berkeley, California
- Department of Global Ecology, Carnegie Institution for Science, Stanford, California
| | - Cho-Ying Huang
- Department of Geography, National Taiwan University, Taipei, Taiwan
- Research Center for Future Earth, National Taiwan University, Taipei, Taiwan
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Reduced Carbon Dioxide Sink and Methane Source under Extreme Drought Condition in an Alpine Peatland. SUSTAINABILITY 2018. [DOI: 10.3390/su10114285] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Potential changes in both the intensity and frequency of extreme drought events are vital aspects of regional climate change that can alter the distribution and dynamics of water availability and subsequently affect carbon cycles at the ecosystem level. The effects of extreme drought events on the carbon budget of peatland in the Zoige plateau and its response mechanisms were studied using an in-field controlled experimental method. The results indicated that the peatland ecosystem of the Zoige plateau functioned as a carbon sink while under the control (CK) or extreme drought (D) treatment throughout the entire growing season. Maximum fluxes of methane (CH4) emissions and the weakest carbon sink activity from this ecosystem were in the early growth stage, the most powerful carbon sink activity was during the peak growth stage, while the absorption sink activity of carbon dioxide (CO2) and CH4 was present during the senescence stage. Extreme drought reduced the gross primary productivity (GPP) and ecosystem respiration (Re) of the peatland ecosystem by 14.5% and 12.6%, respectively (p < 0.05) and the net ability to store carbon was reduced by 11.3%. Overall, the GPP was highly sensitive to extreme drought. Moreover, extreme drought significantly reduced the CH4 fluxes of the ecosystem and even changed the peatland from a CH4 emission source to a CH4 sink. Subsequent to drought treatment, extreme drought was also shown to have a carry-over effect on the carbon budget of this ecosystem. Soil water content and soil temperature were the main driving factors of carbon budget change in the peatland of the Zoige plateau, but with the increase in soil depth, these driving forces were decreased. The findings indicated that frequent extreme drought events in the future might reduce the net carbon sink function of peatland areas, with an especially strong influence on CO2.
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Duan H, Chaszar B, Lewis JD, Smith RA, Huxman TE, Tissue DT. CO2 and temperature effects on morphological and physiological traits affecting risk of drought-induced mortality. TREE PHYSIOLOGY 2018; 38:1138-1151. [PMID: 29701843 DOI: 10.1093/treephys/tpy037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 03/21/2018] [Indexed: 06/08/2023]
Abstract
Despite a wealth of eco-physiological assessments of plant response to extreme drought, few studies have addressed the interactive effects of global change factors on traits driving mortality. To understand the interaction between hydraulic and carbon metabolic traits influencing tree mortality, which may be independently influenced by atmospheric [CO2] and temperature, we grew Eucalyptus sideroxylon A. Cunn. ex Woolls from seed in a full-factorial [CO2] (280, 400 and 640 μmol mol-1, Cp, Ca and Ce, respectively) and temperature (ambient and ambient +4 °C, Ta and Te, respectively) experiment. Prior to drought, growth across treatment combinations resulted in significant variation in physiological and morphological traits, including photosynthesis (Asat), respiration (Rd), stomatal conductance, carbohydrate storage, biomass and leaf area (LA). Ce increased Asat, LA and leaf carbohydrate concentration compared with Ca, while Cp generated the opposite response; Te reduced Rd. However, upon imposition of drought, Te hastened mortality (9 days sooner compared with Ta), while Ce significantly exacerbated drought stress when combined with Te. Across treatments, earlier time-to-mortality was mainly associated with lower (more negative) leaf water potential (Ψl) during the initial drought phase, along with higher water loss across the first 3 weeks of water limitation. Among many variables, Ψl was more important than carbon status in predicting time-to-mortality across treatments, yet leaf starch was associated with residual variation within treatments. These results highlight the need to carefully consider the integration, interaction and hierarchy of traits contributing to mortality, along with their responses to environmental drivers. Both morphological traits, which influence soil resource extraction, and physiological traits, which affect water-for-carbon exchange to the atmosphere, must be considered to adequately predict plant response to drought. Researchers have struggled with assessing the relative importance of hydraulic and carbon metabolic traits in determining mortality, yet an integrated trait, time-dependent framework provides considerable insight into the risk of death from drought for trees.
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Affiliation(s)
- Honglang Duan
- Hawkesbury Institute for the Environment, Hawkesbury Campus, Western Sydney University, Locked Bag 1797, Penrith NSW, Australia
- Jiangxi Provincial Key Laboratory for Restoration of Degraded Ecosystems & Watershed Ecohydrology, Nanchang Institute of Technology, Nanchang, China
| | - Brian Chaszar
- Hawkesbury Institute for the Environment, Hawkesbury Campus, Western Sydney University, Locked Bag 1797, Penrith NSW, Australia
| | - James D Lewis
- Hawkesbury Institute for the Environment, Hawkesbury Campus, Western Sydney University, Locked Bag 1797, Penrith NSW, Australia
- Louis Calder Center - Biological Field Station and Department of Biological Sciences, Fordham University, Armonk, NY, USA
| | - Renee A Smith
- Hawkesbury Institute for the Environment, Hawkesbury Campus, Western Sydney University, Locked Bag 1797, Penrith NSW, Australia
| | - Travis E Huxman
- School of Biological Sciences, University of California, Irvine, CA, USA
| | - David T Tissue
- Hawkesbury Institute for the Environment, Hawkesbury Campus, Western Sydney University, Locked Bag 1797, Penrith NSW, Australia
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Dutta H. Insights into the phenomenon of alien plant invasion and its synergistic interlinkage with three current ecological issues. JOURNAL OF ASIA-PACIFIC BIODIVERSITY 2018. [DOI: 10.1016/j.japb.2018.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Bowman EA, Arnold AE. Distributions of ectomycorrhizal and foliar endophytic fungal communities associated with Pinus ponderosa along a spatially constrained elevation gradient. AMERICAN JOURNAL OF BOTANY 2018; 105:687-699. [PMID: 29756204 DOI: 10.1002/ajb2.1072] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 01/22/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Understanding distributions of plant-symbiotic fungi is important for projecting responses to environmental change. Many coniferous trees host ectomycorrhizal fungi (EM) in association with roots and foliar endophytic fungi (FE) in leaves. We examined how EM and FE associated with Pinus ponderosa each vary in abundance, diversity, and community structure over a spatially constrained elevation gradient that traverses four plant communities, 4°C in mean annual temperature, and 15 cm in mean annual precipitation. METHODS We sampled 63 individuals of Pinus ponderosa in 10 sites along a 635 m elevation gradient that encompassed a geographic distance of 9.8 km. We used standard methods to characterize each fungal group (amplified and sequenced EM from root tips; isolated and sequenced FE from leaves). KEY RESULTS Abundance and diversity of EM were similar across sites, but community composition and distributions of the most common EM differed with elevation (i.e., with climate, soil chemistry, and plant communities). Abundance and composition of FE did not differ with elevation, but diversity peaked in mid-to-high elevations. CONCLUSIONS Our results suggest relatively tight linkages between EM and climate, soil chemistry, and plant communities. That FE appear less linked with these factors may speak to limitations of a culture-based approach, but more likely reflects the small spatial scale encompassed by our study. Future work should consider comparable methods for characterizing these functional groups, and additional transects to understand relationships of EM and FE to environmental factors that are likely to shift as a function of climate change.
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Affiliation(s)
- Elizabeth A Bowman
- School of Plant Sciences, The University of Arizona, Tucson, Arizona, 85721, USA
| | - A Elizabeth Arnold
- School of Plant Sciences, The University of Arizona, Tucson, Arizona, 85721, USA
- Department of Ecology and Evolutionary Biology, The University of Arizona, Tucson, Arizona, 85721, USA
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Kurganova IN, Lopes de Gerenyu VO, Myakshina TN, Sapronov DV, Savin IY, Shorohova EV. Carbon Balance in Forest Ecosystems of Southern Part of Moscow Region under a Rising Aridity of Climate. CONTEMP PROBL ECOL+ 2018. [DOI: 10.1134/s1995425517070071] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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35
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Skelton RP, Brodribb TJ, McAdam SAM, Mitchell PJ. Gas exchange recovery following natural drought is rapid unless limited by loss of leaf hydraulic conductance: evidence from an evergreen woodland. THE NEW PHYTOLOGIST 2017; 215:1399-1412. [PMID: 28620915 DOI: 10.1111/nph.14652] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 05/08/2017] [Indexed: 05/26/2023]
Abstract
Drought can cause major damage to plant communities, but species damage thresholds and postdrought recovery of forest productivity are not yet predictable. We used an El Niño drought event as a natural experiment to test whether postdrought recovery of gas exchange could be predicted by properties of the water transport system, or if metabolism, primarily high abscisic acid concentration, might delay recovery. We monitored detailed physiological responses, including shoot sapflow, leaf gas exchange, leaf water potential and foliar abscisic acid (ABA), during drought and through the subsequent rehydration period for a sample of eight canopy and understory species. Severe drought caused major declines in leaf water potential, elevated foliar ABA concentrations and reduced stomatal conductance and assimilation rates in our eight sample species. Leaf water potential surpassed levels associated with incipient loss of leaf hydraulic conductance in four species. Following heavy rainfall gas exchange in all species, except those trees predicted to have suffered hydraulic impairment, recovered to prestressed rates within 1 d. Recovery of plant gas exchange was rapid and could be predicted by the hydraulic safety margin, providing strong support for leaf vulnerability to water deficit as an index of damage under natural drought conditions.
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Affiliation(s)
- Robert P Skelton
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, 7005, Australia
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Timothy J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, 7005, Australia
| | - Scott A M McAdam
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, 7005, Australia
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Greenwood S, Ruiz-Benito P, Martínez-Vilalta J, Lloret F, Kitzberger T, Allen CD, Fensham R, Laughlin DC, Kattge J, Bönisch G, Kraft NJB, Jump AS. Tree mortality across biomes is promoted by drought intensity, lower wood density and higher specific leaf area. Ecol Lett 2017; 20:539-553. [PMID: 28220612 DOI: 10.1111/ele.12748] [Citation(s) in RCA: 175] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 12/23/2016] [Accepted: 01/16/2017] [Indexed: 12/18/2022]
Abstract
Drought events are increasing globally, and reports of consequent forest mortality are widespread. However, due to a lack of a quantitative global synthesis, it is still not clear whether drought-induced mortality rates differ among global biomes and whether functional traits influence the risk of drought-induced mortality. To address these uncertainties, we performed a global meta-analysis of 58 studies of drought-induced forest mortality. Mortality rates were modelled as a function of drought, temperature, biomes, phylogenetic and functional groups and functional traits. We identified a consistent global-scale response, where mortality increased with drought severity [log mortality (trees trees-1 year-1 ) increased 0.46 (95% CI = 0.2-0.7) with one SPEI unit drought intensity]. We found no significant differences in the magnitude of the response depending on forest biomes or between angiosperms and gymnosperms or evergreen and deciduous tree species. Functional traits explained some of the variation in drought responses between species (i.e. increased from 30 to 37% when wood density and specific leaf area were included). Tree species with denser wood and lower specific leaf area showed lower mortality responses. Our results illustrate the value of functional traits for understanding patterns of drought-induced tree mortality and suggest that mortality could become increasingly widespread in the future.
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Affiliation(s)
- Sarah Greenwood
- Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland
| | - Paloma Ruiz-Benito
- Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland.,Forest Ecology and Restoration Group, Life Sciences Department, Universidad de Alcalá, Science Building, Alcalá de Henares, 28805, Madrid, Spain
| | - Jordi Martínez-Vilalta
- CREAF Cerdanyola del Vallès, Barcelona, 08193, Spain.,Universidad Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain
| | - Francisco Lloret
- CREAF Cerdanyola del Vallès, Barcelona, 08193, Spain.,Universidad Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain
| | - Thomas Kitzberger
- Laboratorio Ecotono, INIBIOMA, CONICET-Universidad Nacional del Comahue, Bariloche, Río Negro, Argentina
| | - Craig D Allen
- U.S. Geological Survey, Fort Collins Science Center, New Mexico Landscapes Field Station, Los Alamos, New Mexico, 87544, USA
| | - Rod Fensham
- Queensland Herbarium, Environmental Protection Agency, Mt Coot-tha Road, Toowong, Qld, 4066, Australia.,School of Biological Sciences, University of Queensland, St Lucia, Qld, 4072, Australia
| | - Daniel C Laughlin
- Environmental Research Institute and School of Science, University of Waikato, Hamilton, New Zealand
| | - Jens Kattge
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Straße 10, 07745, Jena, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig Deutscher Platz 5e, 04103, Leipzig, Germany
| | - Gerhard Bönisch
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Straße 10, 07745, Jena, Germany
| | - Nathan J B Kraft
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
| | - Alistair S Jump
- Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland.,CREAF Cerdanyola del Vallès, Barcelona, 08193, Spain
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Gonzalez‐Akre E, Meakem V, Eng C, Tepley AJ, Bourg NA, McShea W, Davies SJ, Anderson‐Teixeira K. Patterns of tree mortality in a temperate deciduous forest derived from a large forest dynamics plot. Ecosphere 2016. [DOI: 10.1002/ecs2.1595] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Erika Gonzalez‐Akre
- Conservation Ecology Center Smithsonian Conservation Biology Institute Front Royal Virginia 22630 USA
| | - Victoria Meakem
- Conservation Ecology Center Smithsonian Conservation Biology Institute Front Royal Virginia 22630 USA
| | - Cheng‐Yin Eng
- Conservation Ecology Center Smithsonian Conservation Biology Institute Front Royal Virginia 22630 USA
| | - Alan J. Tepley
- Conservation Ecology Center Smithsonian Conservation Biology Institute Front Royal Virginia 22630 USA
| | - Norman A. Bourg
- U.S. Geological Survey National Research Program – Eastern Branch Reston Virginia 20192 USA
| | - William McShea
- Conservation Ecology Center Smithsonian Conservation Biology Institute Front Royal Virginia 22630 USA
| | - Stuart J. Davies
- Center for Tropical Forest Science Smithsonian Tropical Research Institute Panama City 9100 Panama
- Smithsonian National Museum of Natural History Washington D.C. 20013 USA
| | - Kristina Anderson‐Teixeira
- Conservation Ecology Center Smithsonian Conservation Biology Institute Front Royal Virginia 22630 USA
- Center for Tropical Forest Science Smithsonian Tropical Research Institute Panama City 9100 Panama
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38
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Das AJ, Stephenson NL, Davis KP. Why do trees die? Characterizing the drivers of background tree mortality. Ecology 2016; 97:2616-2627. [PMID: 27859135 DOI: 10.1002/ecy.1497] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 04/27/2016] [Accepted: 05/25/2016] [Indexed: 11/10/2022]
Abstract
The drivers of background tree mortality rates-the typical low rates of tree mortality found in forests in the absence of acute stresses like drought-are central to our understanding of forest dynamics, the effects of ongoing environmental changes on forests, and the causes and consequences of geographical gradients in the nature and strength of biotic interactions. To shed light on factors contributing to background tree mortality, we analyzed detailed pathological data from 200,668 tree-years of observation and 3,729 individual tree deaths, recorded over a 13-yr period in a network of old-growth forest plots in California's Sierra Nevada mountain range. We found that: (1) Biotic mortality factors (mostly insects and pathogens) dominated (58%), particularly in larger trees (86%). Bark beetles were the most prevalent (40%), even though there were no outbreaks during the study period; in contrast, the contribution of defoliators was negligible. (2) Relative occurrences of broad classes of mortality factors (biotic, 58%; suppression, 51%; and mechanical, 25%) are similar among tree taxa, but may vary with tree size and growth rate. (3) We found little evidence of distinct groups of mortality factors that predictably occur together on trees. Our results have at least three sets of implications. First, rather than being driven by abiotic factors such as lightning or windstorms, the "ambient" or "random" background mortality that many forest models presume to be independent of tree growth rate is instead dominated by biotic agents of tree mortality, with potentially critical implications for forecasting future mortality. Mechanistic models of background mortality, even for healthy, rapidly growing trees, must therefore include the insects and pathogens that kill trees. Second, the biotic agents of tree mortality, instead of occurring in a few predictable combinations, may generally act opportunistically and with a relatively large degree of independence from one another. Finally, beyond the current emphasis on folivory and leaf defenses, studies of broad-scale gradients in the nature and strength of biotic interactions should also include biotic attacks on, and defenses of, tree stems and roots.
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Affiliation(s)
- Adrian J Das
- U.S. Geological Survey, Western Ecological Research Center, Three Rivers, California, 93271, USA
| | - Nathan L Stephenson
- U.S. Geological Survey, Western Ecological Research Center, Three Rivers, California, 93271, USA
| | - Kristin P Davis
- Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, Colorado, 80523, USA
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Anderegg WRL, Martinez-Vilalta J, Cailleret M, Camarero JJ, Ewers BE, Galbraith D, Gessler A, Grote R, Huang CY, Levick SR, Powell TL, Rowland L, Sánchez-Salguero R, Trotsiuk V. When a Tree Dies in the Forest: Scaling Climate-Driven Tree Mortality to Ecosystem Water and Carbon Fluxes. Ecosystems 2016. [DOI: 10.1007/s10021-016-9982-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Boulanger Y, Gray DR, Cooke BJ, De Grandpré L. Model-specification uncertainty in future forest pest outbreak. GLOBAL CHANGE BIOLOGY 2016; 22:1595-607. [PMID: 26511654 DOI: 10.1111/gcb.13142] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 09/06/2015] [Indexed: 05/16/2023]
Abstract
Climate change will modify forest pest outbreak characteristics, although there are disagreements regarding the specifics of these changes. A large part of this variability may be attributed to model specifications. As a case study, we developed a consensus model predicting spruce budworm (SBW, Choristoneura fumiferana [Clem.]) outbreak duration using two different predictor data sets and six different correlative methods. The model was used to project outbreak duration and the uncertainty associated with using different data sets and correlative methods (=model-specification uncertainty) for 2011-2040, 2041-2070 and 2071-2100, according to three forcing scenarios (RCP 2.6, RCP 4.5 and RCP 8.5). The consensus model showed very high explanatory power and low bias. The model projected a more important northward shift and decrease in outbreak duration under the RCP 8.5 scenario. However, variation in single-model projections increases with time, making future projections highly uncertain. Notably, the magnitude of the shifts in northward expansion, overall outbreak duration and the patterns of outbreaks duration at the southern edge were highly variable according to the predictor data set and correlative method used. We also demonstrated that variation in forcing scenarios contributed only slightly to the uncertainty of model projections compared with the two sources of model-specification uncertainty. Our approach helped to quantify model-specification uncertainty in future forest pest outbreak characteristics. It may contribute to sounder decision-making by acknowledging the limits of the projections and help to identify areas where model-specification uncertainty is high. As such, we further stress that this uncertainty should be strongly considered when making forest management plans, notably by adopting adaptive management strategies so as to reduce future risks.
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Affiliation(s)
- Yan Boulanger
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC, G1V 4C7, Canada
| | - David R Gray
- Natural Resources Canada, Canadian Forest Service, Atlantic Forestry Centre, 1350 Regent Street South, P.O. Box 4000, Fredericton, NB, E3B 5P7, Canada
| | - Barry J Cooke
- Natural Resources Canada, Canadian Forest Service, Northern Forestry Centre, 5320 122nd Street NW, Edmonton, AB, T6H 3S5, Canada
| | - Louis De Grandpré
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC, G1V 4C7, Canada
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Climate Change Vulnerabilities and Adaptation Options for Forest Vegetation Management in the Northwestern USA. ATMOSPHERE 2016. [DOI: 10.3390/atmos7030046] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Anderegg WRL, Hicke JA, Fisher RA, Allen CD, Aukema J, Bentz B, Hood S, Lichstein JW, Macalady AK, McDowell N, Pan Y, Raffa K, Sala A, Shaw JD, Stephenson NL, Tague C, Zeppel M. Tree mortality from drought, insects, and their interactions in a changing climate. THE NEW PHYTOLOGIST 2015; 208:674-83. [PMID: 26058406 DOI: 10.1111/nph.13477] [Citation(s) in RCA: 264] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 04/23/2015] [Indexed: 05/20/2023]
Abstract
Climate change is expected to drive increased tree mortality through drought, heat stress, and insect attacks, with manifold impacts on forest ecosystems. Yet, climate-induced tree mortality and biotic disturbance agents are largely absent from process-based ecosystem models. Using data sets from the western USA and associated studies, we present a framework for determining the relative contribution of drought stress, insect attack, and their interactions, which is critical for modeling mortality in future climates. We outline a simple approach that identifies the mechanisms associated with two guilds of insects - bark beetles and defoliators - which are responsible for substantial tree mortality. We then discuss cross-biome patterns of insect-driven tree mortality and draw upon available evidence contrasting the prevalence of insect outbreaks in temperate and tropical regions. We conclude with an overview of tools and promising avenues to address major challenges. Ultimately, a multitrophic approach that captures tree physiology, insect populations, and tree-insect interactions will better inform projections of forest ecosystem responses to climate change.
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Affiliation(s)
- William R L Anderegg
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, 08540, USA
| | - Jeffrey A Hicke
- Department of Geography, University of Idaho, Moscow, ID, 83844, USA
| | - Rosie A Fisher
- National Center for Atmospheric Research, Boulder, CO, 80305, USA
| | - Craig D Allen
- US Geological Survey, Fort Collins Science Center, Jemez Mountains Field Station, Los Alamos, NM, 87544, USA
| | - Juliann Aukema
- National Center for Ecological Analysis and Synthesis, Santa Barbara, CA, 93117, USA
| | - Barbara Bentz
- USDA Forest Service, Rocky Mountain Research Station, Logan, UT, 84321, USA
| | - Sharon Hood
- Division of Biological Sciences, The University of Montana, Missoula, MT, 59812, USA
| | - Jeremy W Lichstein
- Department of Biology, University of Florida, Gainesville, FL, 32611, USA
| | - Alison K Macalady
- School of Geography and Development, University of Arizona, Tucson, AZ, 85712, USA
| | - Nate McDowell
- Earth and Environmental Sciences Division, Los Alamos National Lab, Los Alamos, NM, 87545, USA
| | - Yude Pan
- Northern Research Station, US Forest Service, Newtown Square, PA, 19073, USA
| | - Kenneth Raffa
- Department of Entomology, University of Wisconsin, Madison, WI, 53706, USA
| | - Anna Sala
- Division of Biological Sciences, The University of Montana, Missoula, MT, 59812, USA
| | - John D Shaw
- Rocky Mountain Research Station, US Forest Service, Ogden, UT, 84401, USA
| | - Nathan L Stephenson
- US Geological Survey, Western Ecological Research Center, 47050 Generals Highway No. 4, Three Rivers, CA, 93271, USA
| | - Christina Tague
- Bren School of Environmental Science and Management, University of California - Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Melanie Zeppel
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
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Allen CD, Breshears DD, McDowell NG. On underestimation of global vulnerability to tree mortality and forest die-off from hotter drought in the Anthropocene. Ecosphere 2015. [DOI: 10.1890/es15-00203.1] [Citation(s) in RCA: 1345] [Impact Index Per Article: 149.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Ferrenberg S, Knelman JE, Jones JM, Beals SC, Bowman WD, Nemergut DR. Soil bacterial community structure remains stable over a 5-year chronosequence of insect-induced tree mortality. Front Microbiol 2014; 5:681. [PMID: 25566204 PMCID: PMC4267275 DOI: 10.3389/fmicb.2014.00681] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 11/20/2014] [Indexed: 12/20/2022] Open
Abstract
Extensive tree mortality from insect epidemics has raised concern over possible effects on soil biogeochemical processes. Yet despite the importance of microbes in nutrient cycling, how soil bacterial communities respond to insect-induced tree mortality is largely unknown. We examined soil bacterial community structure (via 16S rRNA gene pyrosequencing) and community assembly processes (via null deviation analysis) along a 5-year chronosequence (substituting space for time) of bark beetle-induced tree mortality in the southern Rocky Mountains, USA. We also measured microbial biomass and soil chemistry, and used in situ experiments to assess inorganic nitrogen mineralization rates. We found that bacterial community structure and assembly-which was strongly influenced by stochastic processes-were largely unaffected by tree mortality despite increased soil ammonium ([Formula: see text]) pools and reductions in soil nitrate ([Formula: see text]) pools and net nitrogen mineralization rates after tree mortality. Linear models suggested that microbial biomass and bacterial phylogenetic diversity are significantly correlated with nitrogen mineralization rates of this forested ecosystem. However, given the overall resistance of the bacterial community to disturbance from tree mortality, soil nitrogen processes likely remained relatively stable following tree mortality when considered at larger spatial and longer temporal scales-a supposition supported by the majority of available studies regarding biogeochemical effects of bark beetle infestations in this region. Our results suggest that soil bacterial community resistance to disturbance helps to explain the relatively weak effects of insect-induced tree mortality on soil N and C pools reported across the Rocky Mountains, USA.
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Affiliation(s)
- Scott Ferrenberg
- Department of Ecology and Evolutionary Biology, University of ColoradoBoulder, CO, USA
| | - Joseph E. Knelman
- Department of Ecology and Evolutionary Biology, University of ColoradoBoulder, CO, USA
- Institute of Arctic and Alpine Research, University of ColoradoBoulder, CO, USA
| | | | - Stower C. Beals
- Department of Ecology and Evolutionary Biology, University of ColoradoBoulder, CO, USA
- Institute of Arctic and Alpine Research, University of ColoradoBoulder, CO, USA
| | - William D. Bowman
- Department of Ecology and Evolutionary Biology, University of ColoradoBoulder, CO, USA
- Institute of Arctic and Alpine Research, University of ColoradoBoulder, CO, USA
| | - Diana R. Nemergut
- Institute of Arctic and Alpine Research, University of ColoradoBoulder, CO, USA
- Department of Biology, Duke UniversityDurham, NC, USA
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Štursová M, Šnajdr J, Cajthaml T, Bárta J, Šantrůčková H, Baldrian P. When the forest dies: the response of forest soil fungi to a bark beetle-induced tree dieback. THE ISME JOURNAL 2014; 8:1920-31. [PMID: 24671082 PMCID: PMC4139728 DOI: 10.1038/ismej.2014.37] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Revised: 01/24/2014] [Accepted: 02/10/2014] [Indexed: 11/09/2022]
Abstract
Coniferous forests cover extensive areas of the boreal and temperate zones. Owing to their primary production and C storage, they have an important role in the global carbon balance. Forest disturbances such as forest fires, windthrows or insect pest outbreaks have a substantial effect on the functioning of these ecosystems. Recent decades have seen an increase in the areas affected by disturbances in both North America and Europe, with indications that this increase is due to both local human activity and global climate change. Here we examine the structural and functional response of the litter and soil microbial community in a Picea abies forest to tree dieback following an invasion of the bark beetle Ips typographus, with a specific focus on the fungal community. The insect-induced disturbance rapidly and profoundly changed vegetation and nutrient availability by killing spruce trees so that the readily available root exudates were replaced by more recalcitrant, polymeric plant biomass components. Owing to the dramatic decrease in photosynthesis, the rate of decomposition processes in the ecosystem decreased as soon as the one-time litter input had been processed. The fungal community showed profound changes, including a decrease in biomass (2.5-fold in the litter and 12-fold in the soil) together with the disappearance of fungi symbiotic with tree roots and a relative increase in saprotrophic taxa. Within the latter group, successive changes reflected the changing availability of needle litter and woody debris. Bacterial biomass appeared to be either unaffected or increased after the disturbance, resulting in a substantial increase in the bacterial/fungal biomass ratio.
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Affiliation(s)
- Martina Štursová
- Institute of Microbiology of the ASCR, v.v.i., Vídeňská 1083, Praha 4, Czech Republic
| | - Jaroslav Šnajdr
- Institute of Microbiology of the ASCR, v.v.i., Vídeňská 1083, Praha 4, Czech Republic
| | - Tomáš Cajthaml
- Institute of Microbiology of the ASCR, v.v.i., Vídeňská 1083, Praha 4, Czech Republic
| | - Jiří Bárta
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Hana Šantrůčková
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Petr Baldrian
- Institute of Microbiology of the ASCR, v.v.i., Vídeňská 1083, Praha 4, Czech Republic
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Manusch C, Bugmann H, Wolf A. Sensitivity of simulated productivity to soil characteristics and plant water uptake along drought gradients in the Swiss Alps. Ecol Modell 2014. [DOI: 10.1016/j.ecolmodel.2014.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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48
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Weed AS, Ayres MP, Hicke JA. Consequences of climate change for biotic disturbances in North American forests. ECOL MONOGR 2013. [DOI: 10.1890/13-0160.1] [Citation(s) in RCA: 292] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Plaut JA, Wadsworth WD, Pangle R, Yepez EA, McDowell NG, Pockman WT. Reduced transpiration response to precipitation pulses precedes mortality in a piñon-juniper woodland subject to prolonged drought. THE NEW PHYTOLOGIST 2013; 200:375-387. [PMID: 23844951 DOI: 10.1111/nph.12392] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 05/27/2013] [Indexed: 06/02/2023]
Abstract
Global climate change is predicted to alter the intensity and duration of droughts, but the effects of changing precipitation patterns on vegetation mortality are difficult to predict. Our objective was to determine whether prolonged drought or above-average precipitation altered the capacity to respond to the individual precipitation pulses that drive productivity and survival. We analyzed 5 yr of data from a rainfall manipulation experiment in piñon-juniper (Pinus edulis-Juniperus monosperma) woodland using mixed effects models of transpiration response to event size, antecedent soil moisture, and post-event vapor pressure deficit. Replicated treatments included irrigation, drought, ambient control and infrastructure control. Mortality was highest under drought, and the reduced post-pulse transpiration in the droughted trees that died was attributable to treatment effects beyond drier antecedent conditions and reduced event size. In particular, trees that died were nearly unresponsive to antecedent shallow soil moisture, suggesting reduced shallow absorbing root area. Irrigated trees showed an enhanced response to precipitation pulses. Prolonged drought initiates a downward spiral whereby trees are increasingly unable to utilize pulsed soil moisture. Thus, the additive effects of future, more frequent droughts may increase drought-related mortality.
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Affiliation(s)
- Jennifer A Plaut
- Department of Biology, 1 University of New Mexico, MSC03 2020, Albuquerque, NM, 87131-0001, USA
| | - W Duncan Wadsworth
- Department of Statistics, Rice University, MS 138, PO Box 1892, Houston, TX, 77251, USA
| | - Robert Pangle
- Department of Biology, 1 University of New Mexico, MSC03 2020, Albuquerque, NM, 87131-0001, USA
| | - Enrico A Yepez
- Departamento de Ciencias del Agua y del Medio Ambiente, Instituto Tecnológico de Sonora, Ciudad Obregón Sonora, 85000, Mexico
| | - Nate G McDowell
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - William T Pockman
- Department of Biology, 1 University of New Mexico, MSC03 2020, Albuquerque, NM, 87131-0001, USA
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Clifford MJ, Royer PD, Cobb NS, Breshears DD, Ford PL. Precipitation thresholds and drought-induced tree die-off: insights from patterns of Pinus edulis mortality along an environmental stress gradient. THE NEW PHYTOLOGIST 2013; 200:413-421. [PMID: 23772860 DOI: 10.1111/nph.12362] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 05/15/2013] [Indexed: 06/02/2023]
Abstract
Recent regional tree die-off events appear to have been triggered by a combination of drought and heat - referred to as 'global-change-type drought'. To complement experiments focused on resolving mechanisms of drought-induced tree mortality, an evaluation of how patterns of tree die-off relate to highly spatially variable precipitation is needed. Here, we explore precipitation relationships with a die-off event of pinyon pine (Pinus edulis Engelm.) in southwestern North America during the 2002-2003 global-change-type drought. Pinyon die-off and its relationship with precipitation was quantified spatially along a precipitation gradient in north-central New Mexico with standard field plot measurements of die-off combined with canopy cover derived from normalized burn ratio (NBR) from Landsat imagery. Pinyon die-off patterns revealed threshold responses to precipitation (cumulative 2002-2003) and vapor pressure deficit (VPD), with little to no mortality (< 10%) above 600 mm and below warm season VPD of c. 1.7 kPa. [Correction added after online publication 17 June 2013; in the preceding sentence, the word 'below' has been inserted.] Our results refine how precipitation patterns within a region influence pinyon die-off, revealing a precipitation and VPD threshold for tree mortality and its uncertainty band where other factors probably come into play - a response type that influences stand demography and landscape heterogeneity and is of general interest, yet has not been documented.
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Affiliation(s)
- Michael J Clifford
- Earth and Environmental Science Department, Lehigh University, Bethlehem, PA, 18015, USA
| | - Patrick D Royer
- Columbia Basin Groundwater Management Area, Kennewick, WA, 99366, USA
- Intera Geoscience and Engineering, Richland, WA, 99354, USA
| | - Neil S Cobb
- Merriam-Powell Center for Environmental Research, Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - David D Breshears
- Department of Ecology & Evolutionary Biology, School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA
| | - Paulette L Ford
- USDA Forest Service Rocky Mountain Research Station, Albuquerque, NM, 87102, USA
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